The invention relates to a device for taking up and discharging a defined amount of liquid.
G 88 03 331.7 discloses a pipette, in particular for use in dental technology. In this case, an agitating implement is attached to a suction tube. In the case of the known pipette, the liquid must be sucked into the suction tube by means of a suction device. The amount of liquid sucked in depends on the manner and method of actuation of the suction device. It can vary.
EP 0 569 851 A1 describes a pipetting device for the mixing of liquids. In this case, the pipette is connected to a take-up device connected to an eccentric. The device is complex and expensive. It requires, inter alia, a special vacuum line for sucking up the liquid to be pipetted.
JP Patent Abstracts of Japan: 07080331 A discloses a pipette tip with a radially peripheral cover formed onto it.
According to the prior art, a capillary produced from glass is also known for taking up a defined amount of blood. The blood taken up can be forced out of the capillary and transferred into a test tube by means of a rubber bellows or diaphragm which can be fitted onto the capillary. In said test tube, it is stirred with a reagent, usually with the aid of the capillary.
The fitting on of the bellows is laborious. Rupture of the capillary may occur as this takes place. The agitating action which can be produced by the capillary is inadequate.
The object of the invention is to eliminate the disadvantages of the prior art. In particular, a device for taking up and discharging a defined amount of liquid which is easy to handle and with which an improved agitating action can be achieved is to be specified.
According to the invention, the object is achieved by a device for taking up and discharging a defined amount of liquid, an agitating means being provided at a distal end of a capillary and a bellows being provided in the vicinity of a proximal end. The device according to the invention is easy to handle. There is no longer any need for a separate bellows to be pushed into the capillary. The agitating means which can be produced by the capillary is improved.
The bellows may have an aperture. This makes it possible for the liquid to be automatically sucked into the capillary. The liquid can be forced out of the capillary by keeping the aperture closed and squeezing the bellows.
The agitating means is expediently designed in the form of a hook-like continuation, which may have a tip. This simplifies and makes possible in particular the so-called xe2x80x9chookingxe2x80x9d of blood.
According to a further design feature, the bellows may have an accordion-like arrangement of folds. This makes it easier to squeeze.
The capillary, the bellows and the agitating means may be produced in one piece from plastic. This makes production easier and less costly.
According to a further embodiment, the bellows may be formed onto a tubular receptacle, the tubular receptacle being able to taper in the direction of an opening lying opposite the bellows. A capillary produced from glass is expediently fitted frictionally into the tubular receptacle in the region of the opening. This two-part device is also easy to produce. It is possible here to resort to commercially available glass capillaries. The glass capillary is protected against the risk of rupture by being embedded in the tubular receptacle.